**Role:** You are a Creative Developer specializing in "Acid Graphics" and "Brutalist Web Design". You excel at creating unconventional layouts using pure CSS.
**Task:** Develop the "ACID_WAVE" landing page.
**[CONFIGURATION]**
- **[STYLE_NAME]:** Acid Graphics
- **[INDUSTRY]:** Web3 Audio
- **[PROJECT_NAME]:** ACID_WAVE
- **[TECH_STACK]:** HTML5 + Vanilla CSS3 (Embedded).
- **[PAGE_STRUCTURE]:** Navbar, Liquid Hero, Marquee, Grid, Popups, Cassette Pricing, Footer.
**Technical Requirements:**
1. **Global Variables (`:root`):**
- **Acid Palette:** `--theme-primary: #93f20d;` (Acid Green), `--bg-dark: #1b2210;`, `--bg-acid: #0d1108;`.
- **Fonts:** `--font-display: 'Space Grotesk', sans-serif;` (Headings), `--font-mono: 'Courier New', monospace;`.
2. **Key Visual Effects (The "Acid" Look):**
- **Stretched Typography:** Create a utility class `.stretch-text` that uses `transform: scaleY(1.5)` to mimic the distorted rave typography style.
- **Liquid Background:** Use `mix-blend-mode: overlay` or `difference` on an image layer to create a trippy, oil-slick hero background over a dark color.
- **Infinite Marquee:** Implement a pure CSS `@keyframes` animation to scroll a list of text/logos horizontally forever.
- **Retro Popups:** Style the testimonial cards to look like old OS windows (Bevel borders: `border-color: white black black white; border-width: 2px;`).
3. **Specific Components:**
- **Pricing Cassettes:** Use CSS borders and pseudo-elements (`::before`, `::after`) to draw the screw holes and "Side A/B" labels of a cassette tape.
- **Scrollbar:** A custom, thick scrollbar with sharp edges and acid green thumb.
4. **Layout Philosophy:**
- Use **CSS Grid** for rigid alignment.
- Borders should be thin (1px) and visible (`rgba(255,255,255,0.1)`) to emphasize the structure.
- Avoid rounded corners (keep `border-radius` at 0 or very small, e.g., 2px).